Integrated diamond carrier method for laser bar arrays

ABSTRACT

A method of making efficient Integrated Diamond Carrier heat sink and mounting structures usable typically to mount the solid-state laser bars often employed for pumping high power lasers, for example. The disclosed method forms the Integrated Diamond Carrier on a shaped sacrificial substrate member by chemical vapor deposition growing of diamond on a patterned substrate, made from for example silicon semiconductor. The substrate serves as a mold and is etched away after Integrated Diamond Carrier base plate formation leaving the freestanding diamond carrier. Optically usable surfaces are achieved on the Integrated Diamond Carrier through use of substrate crystal plane characteristics and an improved deposition arrangement.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication No. 60/557,451, “INTEGRATED DIAMOND CARRIER (IDC) FOR LASERBAR ARRAYS”, filed on 29 Mar. 2004. The contents of this provisionalapplication are hereby incorporated by reference herein.

CROSS REFERENCE TO RELATED PATENT APPLICATION

The present document is somewhat related to the co pending and commonlyassigned patent application document “INTEGRATED DIAMOND CARRIER FORLASER BAR ARRAYS”, Ser. No. 11/091,684, filed of even date herewith. Thecontents of this somewhat related application are hereby incorporated byreference herein.

RIGHTS OF THE GOVERNMENT

The invention described herein may be manufactured and used by or forthe Government of the United States for all governmental purposeswithout the payment of any royalty.

BACKGROUND OF THE INVENTION

The ability to cool a laser diode has been widely recognized as alimitation of current day ability to convert electrical energy intocoherent radiant energy in a small space. Since present day laser diodesoperate in the realm of fifty percent or lower electrical energy tolight energy conversion efficiency and laser diode operation in thetemperature range around room temperature are usual factors incurred inlaser operation, it is easy to comprehend that efficient removal ofunconverted electrical energy proceeds or energy losses, i.e., heat,from a for example, laser bar structure is highly desirable.

One of the better heat removal arrangements currently known in the laserdiode art originates in commendable work accomplished by a team ofspecialists working in the Lawrence Livermore National Laboratory(Lawrence), a United States Government owned laboratory operated for theGovernment of the U.S. by the University of California. The Lawrencecooling arrangement involves a Silicon Monolithic Microchannel (SiMM)apparatus in which a liquid such as water flowing in an array of closedcross section sub surface channels accomplishes the ultimate removal ofheat from a laser diode array. Several U.S. patents describe theLawrence cooling arrangement; these patents include U.S. Pat. No.5,828,683. Several other U.S. patents relating to such cooling, patentsby Lawrence colleagues and others, are identified in the list ofreferences submitted with the present patent application. Each of thesepatents, the other patents identified in connection with the presentapplication and the publication references identified in connection withthe present application are hereby incorporated by reference herein.

A brief consideration of characteristics of the best available laserdiode Silicon Monolithic Microchannel cooling arrangement illustratesthe existence of need in the art for even more improved laser diodethermal management tools. To this end the thermal resistance of theLawrence Silicon Monolithic Microchannel apparatus is estimated to beapproximately 0.05 degree Celsius/Watt for a 1 cm² area due to thethermal conductivity of the employed silicon and the thickness of thecarrier structure. For a hypothetical thermal load of 1000 Watts/cm²that may occur during high power operation of a laser bar, this meansthe temperature of the top laser mounting surface of the SiliconMonolithic Microchannel will be about 50 degrees Celsius higher than thetemperature of the cooling or bottom surface of the Silicon MonolithicMicrochannel. Hence it may be appreciated that the efficiency of theSilicon Monolithic Microchannel cooling system is reduced by thermalresistance. In the case of the present invention Integrated DiamondCarrier, the difference between the top laser mounting surface and thatof the cooling or bottom surface is only 1 degrees Celsius however as isexplained below.

The Silicon Monolithic Microchannel incorporates a cooling system builtinto the carrier itself, however it incurs difficulties relating totemperature variations from the cooling liquid flow directionality, andwith conditions relating to high heat loads. In the latter instance thepressure of the cooling liquid necessary to cool effectively is oftenexcessively high and can damage the built in Silicon MonolithicMicrochannel cooling channels. In addition, the Silicon MonolithicMicrochannel built in cooling channels are complex and expensive tofabricate.

Other more traditional laser diode packages include arrangements whereinlaser bars or other sources of heat loss are clamped between copperplates and mounted on a common carrier. In these arrangements, heat isremoved from the laser through the copper plates by the cooling system.The overall thermal resistances achieved with these types of packagesare however usually even higher than that incurred with the SiliconMonolithic Microchannel.

Additionally fabrication of a Silicon Monolithic Microchannel device andthe more traditional laser bar packages are notably more complex thanthe simple planar fabrication process of the present invention IDC;especially when the manner in which conventional devices direct thelaser beams is considered. Notably the arrangement of the presentinvention IDC is also well suited for use with highly efficient liquidspray cooling techniques.

As may be appreciated by even a cursory review of the publicationreferences identified in connection with the present application it hasfor years been suggested that laser diode heat sinks or heat transferelements made from diamond material can be of assistance in the removalof heat energy losses from a laser diode, a solid state laser. Indeed anumber of diamond-inclusive thermal energy management arrangements forsuch diodes have been disclosed over a period of some thirty or soyears. The present invention provides an especially advantageousimprovement in this area.

SUMMARY OF THE INVENTION

The present invention provides a fabricated diamond substrate mountingfor an array of semiconductor laser diode bars.

It is therefore an object of the present invention to provide a laserdiode substrate member of high thermal conductivity and low thermalresistance.

It is another object of the invention to fabricate a laser diodemounting having an integral light deflecting element.

It is another object of the invention to fabricate a laser diodesubstrate structure inclusive of low thermal resistance and selectedstable laser beam reorientation characteristics.

It is another object of the invention to fabricate a laser diodemounting arrangement enabling longer operating life from a laser diodeassembly.

It is another object of the invention to provide a laser diode mountingarrangement capable of convenient and conventional process fabrication.

It is another object of the invention to provide a laser diode mountingarrangement characterized a sacrificial intermediate material used inits realization process.

It is another object of the invention to employ a substrate removalprocess in fabricating a laser diode mounting structure.

It is another object of the invention to achieve a laser IntegratedDiamond Carrier through use of an improved chemical vapor depositionprocess.

It is another object of the invention to provide a chemical vapordeposition process capable of achieving optically acceptable depositedsurfaces.

It is another object of the invention to provide a chemical vapordeposition process employing controlled differing deposition rates.

It is another object of the invention to provide an improved diamondchemical vapor deposition process inclusive of a plurality of processcomponent and parameter variations.

These and other objects of the invention will become apparent as thedescription of the representative embodiments proceeds.

These and other objects of the invention are achieved by the method ofmaking a heat conducting substrate for physical mounting, effectivethermal cooling and output light orientation of a plurality ofsemiconductor laser bar members, said method comprising the steps of:

fabricating a substratum element having an array of surface featuresinversely relating to physical structure contemplated in said heatconducting substrate;

said fabricating step including a plurality of photoresist depositingand developing steps and substratum element etching steps;

said plurality of photoresist depositing and developing steps andsubstratum etching steps forming a first array of flat bottomedelongated inverse pedestal channel regions across a surface portion ofsaid substratum element;

said plurality of photoresist depositing and developing steps andsubstratum etching steps also forming a second array of multiplanarsloping bottom elongated inverse optical element channel regions,interspersed with said flat bottomed elongated inverse pedestal channelregions, across said surface portion of said substratum element;

covering said substratum element including said first array of flatbottomed elongated inverse pedestal channel regions and said secondarray of multiplanar sloping bottom elongated inverse optical elementchannel regions with a deposited layer of thermally conductive substrateforming material;

etching away said substratum element from said layer of thermallyconductive substrate forming material.

BRIEF DESCRIPTION OF THE DRAWINGS

This patent or application file contains at least one photographexecuted in color. Copies of this patent or patent applicationpublication with color drawing(s) will be provided by the Office uponrequest and payment of the necessary fee.

The accompanying drawings incorporated in and forming a part of thespecification, illustrate several aspects of the present invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1 shows a perspective view of a single pattern Integrated DiamondCarrier with laser diode arrays.

FIG. 2 shows an assembly of FIG. 1 Integrated Diamond Carriers.

FIG. 3 shows an Integrated Diamond Carrier fabrication mold or template.

FIG. 4 shows surface roughness details of a Integrated Diamond Carrierdeflecting element mold.

FIG. 5 shows an example of surface roughness details of a IntegratedDiamond Carrier deflecting element surface.

FIG. 6 shows an example of surface roughness details for a laser bondingpad portion of an Integrated Diamond Carrier.

FIG. 7 shows an additional example of surface roughness details andcurvature for a laser bonding pad portion of an Integrated DiamondCarrier.

FIG. 8 a shows an Integrated Diamond Carrier surface achievable with aconventional processing arrangement in a low magnification.

FIG. 8 b shows the FIG. 8 a Integrated Diamond Carrier surface withgreater magnification.

FIG. 9 a shows an Integrated Diamond Carrier surface achievable with analternate processing arrangement in a low magnification.

FIG. 9 b shows the FIG. 9 a Integrated Diamond Carrier surface withgreater magnification.

FIG. 10 a shows an Integrated Diamond Carrier surface achievable withprocessing according to the present invention in a low magnification.

FIG. 10 b shows the FIG. 10 a Integrated Diamond Carrier surface withgreater magnification.

FIG. 11 shows a thermal conductivity comparison involving presentinvention Integrated Diamond Carrier materials and other thermalconductors.

FIG. 12 a shows a first thermal path arrangement for a comparison of thepresent invention.

FIG. 12 b shows a second thermal path arrangement for comparison of thepresent invention.

FIG. 13 a shows a comparison of thermal cooling capability for an 808 nmBroad Area laser with 60 um ridge widths according to the presentinvention.

FIG. 13 b shows a comparison of thermal cooling capability for an 808 nmBroad Area laser with 80 um ridge widths according to the presentinvention.

DETAILED DESCRIPTION

It is contemplated that alternative methods and fabrication materialsmay be employed to fabricate Integrated Diamond Carriers according tothe present invention. It is also contemplated that Integrated DiamondCarriers according to the present invention can be utilized in a varietyof packages for a variety of devices and modules in addition to lasers.For example, Integrated Diamond Carriers according to the presentinvention may employ mold or template fabrication materials other thansilicon and may be utilized in the packaging of MicroElectro MechanicalSystems (MEMS) and Micro Optical Electro Mechanical Systems (MOEMS)devices, particularly where such devices can benefit from carrierscustomized to particular applications. Integrated Diamond Carriersaccording to the invention may also find use in the mounting and coolingof semiconductor devices particularly power semiconductor devices andsemiconductor devices employing optical input or output communicationpaths.

Additionally it is noted that terms such as “preferably,” “commonly,”“essentially,” “critically,” and “typically” are not utilized herein tolimit the scope of the claimed invention or to imply that certainfeatures are critical, essential, or even important to the structure orfunction of the claimed invention. Rather, these terms are merelyintended to highlight alternative or additional features that may or maynot be utilized in a particular embodiment of the invention. Havingdescribed the invention in detail and by reference to specificembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein as preferredor particularly advantageous, it is contemplated that the invention isnot necessarily limited to these preferred aspects.

The Integrated Diamond Carrier of the present invention may be describedas a freestanding diamond baseplate or carrier consisting of an array ofmesa structures for mounting solid state (e.g. GaAs) laser bars andmirrors for steering the generated laser light. The Integrated DiamondCarrier is formed by conformally growing diamond on a patternedsubstrate of for example Silicon that serves as a mold or template. Thesubstrate is etched away leaving the freestanding diamond carrier. Theconformal growth of diamond is important to the successful fabricationof the Integrated Diamond Carrier. For this we prefer a modified versionof a novel nucleation method, as is disclosed in the U.S. patentapplication of S. Z. Rotter, one of the inventors of the presentinvention, in an application titled “Method of Surface Processing inPreparation for Thin Film Coatings” identified with U.S. Ser. No.09/580,230 and filed on May 28, 2000. The contents of this applicationare also hereby incorporated by reference herein. The Rotter process hasbeen found to fabricate diamond films having desirable conformality.Other techniques for conformally coating diamond may also be used.

FIG. 1 in the drawings shows a simplified Integrated Diamond Carrierassembly 100 according to the present invention in a simulatedthree-dimensional view. In the FIG. 1 drawing there appears anIntegrated Diamond Carrier 110 on which is mounted three laser barassemblies 102, 104 and 106 that are disposed in close lateraladjacency. Each of the laser bar assemblies 102, 104 and 106 generates aplurality of light output beams 108, one beam from each of the solidstate or diode laser devices located in the bar assembly. These outputbeams are generally disposed in a common plane and aimed in a commondirection. The number of lasers in each of the laser bar assemblies mayof course vary as may the number of and the size of the laser barassembly itself.

Light beams generated in the laser bar assemblies are shown in FIG. 1 toimpinge on a reflective surface 116 disposed on an optical element suchas the prism 114 made as a part of the pattern of the Integrated DiamondCarrier 110. Laser beams reflected from the surface 116 are directedaway from the FIG. 1 assembly as shown at 120 for collection into ahigher energy beam and utilization. The integral nature of the prism 114is a significant aspect of the present invention in that the shape anddimensions of the FIG. 1 assembly can be established and maintained witha significant degree of precision and long term predictability. TheIntegrated Diamond Carrier 110 and the prism 114 are integral with eachother and are preferably made from chemical vapor deposition-formeddiamond materials as disclosed previously and in successive parts of thepresent document. This diamond provides good physical stability and thehigh thermal conductivity desired in the FIG. 1 structure.

The laser bar elements 102, 104 and 106 are shown in FIG. 1 to bemounted on a mesa pedestal portion 111 of the Integrated Diamond Carrier110 in order to cause the output beams of the arrays to impinge on acentral portion of the prism reflecting surface 116 notwithstanding areasonable degree of output beam angular displacement in the FIG. 1vertical and horizontal directions and to accommodate small nonhorizontal components in the surface of the mesa pedestal at 112. Otherarrangements of these interrelated details are clearly possible andwithin the realm of choice to a designer.

It is notable in the FIG. 1 drawing that the output beams from the laserbar elements 102, 104 and 106 originate from a near bottom surfaceregion of the packages of the elements 102, 104 and 106. Thisarrangement is intentional in the FIG. 1 assembly and occurs by way ofthe laser bar elements 102, 104 and 106 being mounted in what may bedescribed as an upside down or “P side down” or “face down”configuration. This configuration is desirable in order to place thelaser components of the bar array elements 102, 104 and 106 as close aspossible to the receiving surface 112 of the Integrated Diamond Carrier110. Such location minimizes the length of the thermal path from thelaser diode components through laser semiconductor layers into the heatsinking and heat communicating material of the Integrated DiamondCarrier 110.

In addition it is desirable for a thin layer of material such as anadhesion layer of Titanium/Gold of about 100 nanometers thickness and anoverlying layer of Indium of about one to ten microns thickness to beapplied to the pedestal or mesa 111 receiving surface 112 in order toboth better retain the laser bar assemblies 102, 104 and 106 againstremoval forces and to enhance the thermal path integrity between laserand diamond material. The Indium film used may have a nominal thicknessnear three micrometers and may be applied during the chemical vapordeposition sequence for the FIG. 1 assembly.

Other details relating to the Integrated Diamond Carrier 110 also appearin the FIG. 1 drawing, these details include the dimensions inmicrometers that are representative of features in a typical embodimentof the invention. These dimensions are of course not critical and areshown for example rather than for limiting purposes. Additionallyappearing in the FIG. 1 drawing is the generally rough planar surface118 of the backside area of the Integrated Diamond Carrier 110. Thissurface may be exposed to a source of liquid or vapor cooling or phasechange cooling or possibly to metallic thermal conductors in order toconvey laser heat from the FIG. 1 assembly. Clearly some considerationis needed with respect to the nature of the thermal media involved withthis backside surface 118 in order for it to be in keeping with the lowthermal resistance achieved within the FIG. 1 assembly itself.

Fabrication of the FIG. 1 assembly has been said herein to be preferablyaccomplished using the assistance of a mold or jig that may be forexample made of a semiconductor material, a material readily processedto form the FIG. 1 shapes via use of the photoresist, etching, and otherprocesses employed to fabricate integrated circuits. These processes arein fact determinative of shapes appearing in the FIG. 1 embodiment ofthe Integrated Diamond Carrier invention. The angles appearing in theprism 114 in FIG. 1, including the angle at which the surface 116 isdisposed, is in fact most readily achieved through observance of thecrystal properties of the for example Silicon material used in the moldor substrate forming the FIG. 1 diamond assembly. Additional dimensionaldetails of the FIG. 1 assembly appear in the FIG. 3 drawing; details ofthe Integrated Diamond Carrier fabrication process appear below.

FIG. 2 in the drawings shows the appearance of a somewhat practicalembodiment of the Integrated Diamond Carrier, an embodiment providingfor use of a greater number of laser bar assemblies such as shown at102, 104 and 106 in FIG. 1 in for example a higher power laser pumpingarrangement. The FIG. 2 Integrated Diamond Carrier is in fact shown tobe of eight-row capacity or eight times the size of the FIG. 1Integrated Diamond Carrier.

Growing an Integrated Diamond Carrier

In order to fabricate an Integrated Diamond Carrier according to thepresent invention a sequence of steps such as described in the followingparagraphs may be used. Alternate steps are included in thesedescriptions and taken together with the recited preferred steps may beunderstood to comprise a plurality of examples of fabricating IntegratedDiamond Carriers. A first step in these examples is to fabricate apatterned substrate to serve as a “mold” from which the shape of theIntegrated Diamond Carriers can be conformally grown. Preferably thesubstrate “mold” is formed from a single crystal silicon wafer usingconventional photolithography lift off techniques. Photolithographymasks can be accomplished to create the inverse patterns of both themesa structures for mounting the laser bars and the pyramidal mirrorstructures. FIG. 3 in the drawings shows details of a single IntegratedDiamond Carrier mold created by way of such mask procedures. Thepatterned molds can be fabricated from other materials including, butnot limited to silicon, silicon dioxide, aluminum nitride, quartz,sapphire, titanium, copper. Other procedures including, but not limitedto negative or positive photolithographic mask techniques using chemicalwet etching and (deep) reactive ion etching, and laser patterning mayalso be used to achieve the FIG. 3 type of mold. The following examplesof achieving patterns for IDC mold illustrate in more detail some of thepossible variations.

EXAMPLE 1

A silicon pattern having a 1100 micrometer wide flat trench of 150micrometers depth formed by deep reactive ion etching and disposed sothat the v-groove laser bar assemblies mesa begins 100 micrometers fromthe flat trench is achieved in this example; this structure is shown inFIG. 3. A second pattern in the FIG. 3 fabrication sequence produces thev-groove structure of 425 micrometers width at the opening and 300micrometers depth, to the point of the v-groove, using wet etching (e.g.KOH solution) techniques. The v-groove is derived from the natural stopetch plane of the silicon substrate crystal at the 54.7 degrees of angleof the {111} surface of silicon.

EXAMPLE 2

A silicon pattern formed using wet etching (KOH solution) techniques toproduce a v-groove structure 425 micrometers wide at the opening and 300micrometers deep as shown in FIG. 3 is repeated across a silicon moldwafer every 1725 micrometers in order to achieve a full wafer complementof molds and a full wafer of Integrated Diamond Carrier structures.(I.e., the Flat trench and v-groove patterns repeat across the siliconwafer in order to fabricate a full wafer complement of molds andIntegrated Diamond Carrier structures.) The individual molds in thisexample appear as in FIG. 3; a multiple collection of these molds, notshown in the drawings, is used.

EXAMPLE 3

A silicon pattern formed using wet etching (KOH solution) techniques toproduce a 2500 micrometer wide flat trench at 50 micrometers deep withside walls at an angle of 54.7 degrees so that the opening isapproximately 2640 micrometers wide and aligned so that a v-groovestructure begins 10 micrometers from the flat trench is achieved in thisexample. This second pattern will also produce a v-groove structure 425micrometers wide at the opening and 300 micrometers deep to the pointusing wet etching KOH solution techniques. The Flat trench and v-groovepatterns are repeated every 3285 micrometers across the silicon wafer.Molds of this configuration accommodate laser bar assemblies ofdiffering physical and electrical size and differing output and heatloss characteristics than have been described heretofore herein.

EXAMPLE 4

A machined mold or a reproduction of a master machined mold may also beused to accomplish the function of the FIG. 3 mold. Such a mold ofcourse excludes the favored {111} or other crystal plane feature of theFIG. 3 mold and thus may provide any angular shape desired for theillustrated pyramidal mirror element. Such a mold may also needdiffering mold removal reagents in comparison with molds made of siliconor other semiconductor materials. The polishing, plating and othersurface preparation steps contemplated for the surface of the siliconsemiconductor mold also require change or adjustment in accommodation ofthe possibly metal or other mold fabrication material and the degree ofoptical surface quality achieved as a result of the machining operation.With the greater freedom of light diverting element shape achievablewith such a non semiconductor mold the possibility of a refractiverather than reflective diverting of the laser beams is possible. One ormore of the silicon dioxide, aluminum nitride, quartz, sapphire,titanium, copper and other mold materials disclosed above may be usedwith molds made by such machining or other non semiconductor etchingachieved molds.

Once a mold is achieved in one of these manners the desired IntegratedDiamond Carrier can be made using a planar fabrication process in orderto produce a patterned freestanding integral diamond structureconsisting of both mesa elements for mounting solid state laser bars anddiverter elements for directing the light emitted by the edge emittinglaser bars. The integral diamond structure may receive for examplegallium arsenide laser assemblies. The integral light diverters arepyramidal structures of the same diamond material as that composing theremainder of the Integrated Diamond Carrier. This patterned freestandingintegral diamond structure is formed by conformally growing diamond onthe patterned substrate serving as a mold. Once the conformal diamondfilm is grown to the desired thickness (ranging from 50 to 3000micrometers), the patterned substrate is etched away leaving thefreestanding diamond structure.

The chemical vapor deposited (CVD) diamond contemplated for theIntegrated Diamond Carrier of the present invention, and diamond ingeneral, are naturally highly chemically resistant so that regardless ofthe etch technique and mold materials used, the mold substrate can beremoved without significantly affecting the diamond or its form as longas temperatures remain below 1000 degrees Celsius. For example a siliconsubstrate for a Integrated Diamond Carrier may be removed using asolution of hydrofluoric acid (HF), nitric acid (HNO₃) and acetic acid(CH₃COOH) at a ratio of HF:HNO₃:CH₃COOH=3:5:3. Alternatively, a silicondioxide substrate can be removed using a commercial buffered oxide etchsolution.

Prior to growing the diamond film on the patterned substrate, thesubstrate may be (1) cleaned with common solvents (such as acetone,methanol, isopropyl alcohol, ethanol) and rinsed with de-ionized water.Alternately, (2) when using the silicon patterned substrates thesubstrate may be cleaned with common solvents and a thin layer of oxide(e.g. SiO_(x)) formed on the silicon by heating to 900 degrees Celsiusin an oxygen atmosphere, then just prior to inserting the sample intothe diamond deposition chamber, the oxide layer removed (using either abrief hydrofluoric acid or buffered oxide etch) and the substrate rinsedwith de-ionized water. The purpose of the surface oxidation is to removefrom the substrate any adventitious carbon or other materials that arenot removed with a simple solvent cleaning. A light oxygen plasma etchcan be used to serve the same function.

The conformal growth of diamond is desirable for the successfulfabrication of the Integrated Diamond Carrier. For this we need acontrolled growth process that allows for very dense interface of thediamond and the substrate pattern as well as for a very smoothinterface, especially for fabricating the mirrors. The smoothness of theinterface and hence, the surface of the Integrated Diamond Carrier is afunction of both the quality and smoothness of the substrate pattern andthe control of the diamond nucleation and growth process at theinterface. The Integrated Diamond Carrier surface requires very smoothsurfaces to facilitate mounting of the laser bars, to achieve uniformityof the temperature across the laser bars, to control temperaturegradients in the array (this relates to the heat spreading capability ofthe Integrated Diamond Carrier) and to minimize the amount of light lostby scattering from the mirror structures.

FIG. 4 in the drawings shows a processed atomic force microscopy imageof the surface of the v-groove trench in an achieved silicon pattern.The root mean square roughness appearing in the FIG. 4 photograph is onthe order of 1.6 nanometers. FIG. 5 shows a similarly processed atomicforce microscopy image of the surface roughness of the resultingpyramidal structure of the Integrated Diamond Carrier. The root meansquare roughness in FIG. 5 is on the order of 2.9 nanometers. Thesurface roughness of the flat mesa structure depends largely on the etchtechnique used during formation of the mold silicon pattern. Using deepreactive ion etching a surface roughness between 10 and 220 nanometersand a curvature on the order of 1.5×10⁻⁶ micrometers⁻¹ can be achievedas is shown in the photographs of FIG. 6 and FIG. 7 herein. The FIG. 7photograph is shown in color in the originally filed application of thepresent document in view of the detailed information and measuringscales disclosed therein. When surface roughness of the flat mesastructure is critical, then chemical etch such as with KOH orlaser-etching procedures may be employed for this surface. Chemicaletching results in a surface roughness on the order of 2.9 nanometers.The surface roughness of the IDC is between 2 and 250 nanometersdepending on the procedures used to pattern the substrate “mold”.

A controlled growth process may be used to obtain a very dense diamondfilm at the diamond/substrate interface while growing an IntegratedDiamond Carrier according to the present invention. This process may bea modified and improved version of the process disclosed by an inventoralso named with respect to the present patent document i.e., one Dr.Shlomo Rotter, in the U.S. patent application identified as 09/580,230and filed on May 28, 2000. This application is hereby incorporated byreference herein. Dr. Rotter's process may be referred-to by the acronymNNP (novel nucleation process).

The NNP process is helpful but not entirely successful in growing thedense interface needed for the present invention Integrated DiamondCarrier. This degree of success may be appreciated from the laterdiscussed photographs appearing in the FIG. 9 a and FIG. 9 b drawingsherein. This partial success may in part be attributed to interactionwith the presently preferred plasma assisted microwave chemical vapordeposition system used for diamond growth. Other nucleation and filmgrowth techniques have been described in the literature and may also besuitable for growing the dense conformal diamond coating for the presentinvention Integrated Diamond Carrier. Following is a description of whatwe call the modified novel nucleation process (or MNNP). The modifiednovel nucleation process is a three-step sequence for achieving a highnucleation rate of diamond on a multitude of substrates and obtaining adense smooth interface.

The growth sequences described in this document may accomplished in anapparatus such as the Astex 5 KW Microwave High Growth Chemical VaporDeposition Diamond System, a system operating at a microwave frequencyof 2.45 gigahertz. Alternately a hot filament reactor growth chamberapparatus using a rod array filament, an apparatus known in thedeposition art may be used.

Step 1 in the modified novel nucleation process is referred to as apretreatment step. In this step the cleaned substrate is inserted into adeposition chamber and exposed to what is referred to as “growthconditions” for a period of time ranging from 10 to 90 minutes.Typically this time can be between 30 and 60 minutes. Growth conditionsare relatively arbitrary at this stage. Such conditions are simply thoseconditions for which using any particular diamond deposition technique,e.g. such as hot filament, microwave chemical vapor deposition andso-on, one would normally expect to grow diamond on a properly seededsample. In fact the pretreatment step may be performed at any range ofgrowth conditions, and in almost any type of diamond reactor, and yetachieve the desired effect; the effect of producing a 5 to 10 nanometerthick film of cabonaceous material serving as a uniform adhesion layerfor diamond seeding during step 2. Ellipsometry measurements suggestthat the desired film has the same optical constant as diamond.

Using microwave chemical vapor deposition, MWCVD, and 2.45 Ghzcontinuous wave microwave energy, typical pretreatment conditions can bein the following ranges:

A hydrogen flow rate of 400-900 sccm,

A methane flow rate of 1-9 sccm,

The ratio of methane to hydrogen gas flow rates not to exceed 2%,

An input Power level of 1500 to 4000 Watts,

A pressure of 20 to 120 Torr,

A Temperature of 500 to 900 degrees Celsius.

Step 2 is referred to as the seeding step. In this step, the pretreatedsample is suspended loosely from a corner into a suspension ofnanodiamond powder and ethanol that is continuously agitatedultrasonically. The preferred nanodiamond powder is produced by a commondetonation processes. The average crystal size is 5 nanometers andaverage grain size is 20-50 nanometers. In powder form the material doesagglomerate to sizes that exceed 1 micron. A typical preferrednanopowder solution consists of 2 grams of the described diamondnanopowder in 200 milliliters of ethanol. The solution is agitated forseveral minutes in the ultrasonic bath prior to suspending thepretreated substrate completely into the suspension. The substrateshould be held vertically but be allowed to move freely in thesuspension to obtain the most uniform seeding. Seeding time ranges from10 to 90 minutes; typical times range from 15 to 30 minutes. Afterseeding for the desired length of time the sample is removed from thesolution, initially rinsed in ethanol and placed in an ultrasonic bathof pure ethanol for 2-5 minutes. Finally the sample is removed,initially rinsed in de-ionized water and placed in a ultrasonic bath ofde-ionized water for 2 to 5 minutes; then the moisture is removed fromthe surface by blowing the sample dry with compressed dry nitrogen.Alternatively, to rinsing in an ultrasonic bath, the sample may berinsed with ethanol and de-ionized water by using a spin coatingapparatus.

Several different seeding solutions have also been used successfully toobtain sufficient nucleation sites with this process. Below is discloseda partial list of these solutions:

EXAMPLE 1

As described above, 2 grams of nanodiamond powder in 200 ml of ethanol.

EXAMPLE 2

3.2 grams of 10 micrometer diamond powder in 200 ml of methanol.

EXAMPLE 3

3.2 grams of 10 micrometer diamond powder in 200 ml of ethanol.

EXAMPLE 4

2.2 grams of 10 micrometer diamond powder, 1 gram of 0.1 micrometerdiamond powder in 200 ml of methanol.

EXAMPLE 5

2.2 grams of 10 micrometer diamond powder, 1 gram of 0.1 micrometerdiamond powder in 200 ml of ethanol.

EXAMPLE 6

1.6 grams of 10 micrometer diamond powder, 1.6 grams of 0.1 micrometerdiamond powder in 200 ml of methanol.

EXAMPLE 7

1.6 grams of 10 micrometer diamond powder, 1.6 grams of 0.1 micrometerdiamond powder in 200 ml of ethanol.

EXAMPLE 8

1.0 grams of 10 micrometer diamond powder, 2.2 grams of 0.1 micrometerdiamond powder in 200 ml of methanol.

EXAMPLE 9

1.0 grams of 10 micrometer diamond powder, 2.2 grams of 0.1 micrometerdiamond powder in 200 ml of ethanol.

EXAMPLE 10

3.2 grams of 0.1 micrometer diamond powder in 200 ml of methanol.

EXAMPLE 11

3.2 grams of 0.1 micrometer diamond powder in 200 mL ethanol

EXAMPLE 12

200 ml of General Electric Company diamond slurry 0-0.2 micrometerdiamond formula K-285T.

EXAMPLE 13

200 ml of South Bay Technology diamond suspension 0.1 micron diamond,PIN DS001-16.

EXAMPLE 14

200 ml of Warren Superabrasives diamond suspension, 0.5 micrometerdiamond, type MB DIA-SOL, Lot 910T-6.

It is desirable that the excess slurry, or suspension diamond materialbe fully removed from the substrate by rinsing with the appropriatesolvents and de-ionized water in order to obtain a very finely seededsurface free of contaminants and large agglomerates of diamondparticles. Contaminants and large agglomerates of diamond particlesdegrade the quality of the interface layer between the substrate and thediamond film, increase the surface roughness at the interface and canresult in large gaps between grain boundaries in the film.

Step 3 is referred to as the Growth stage. During this step, the seededand rinsed sample is placed in a growth chamber and the diamond film ofthe Integrated Diamond Carrier work piece is grown on the substrate. Asa result of steps 1 and 2, immediate film growth occurs. There is noinduction period. The density of the grains at the interface and thesize of the nondiamond carbon domains is a function of both the seedingprocess and the initial conditions during the step 3 growth stage. Withappropriate choice of growth conditions and seeding parameters, acontinuous film develops within 40 to 80 nanometers of thickness withgaps of less than 1 nanometer in size between grains. These gaps areusually domains of nondiamond carbon.

The photographs of FIG. 8 a, FIG. 8 b, FIG. 9 a, FIG. 9 b, FIG. 10 a andFIG. 10 b “drawings” herein illustrate the importance of selecting theappropriate growth and seeding conditions in this process; the FIG. 9 aand FIG. 9 b photographs in this group relate to the above describedprocess of Dr. Rotter; the drawings of FIG. 10 a and FIG. 10 b relate tothe herein described process and the photographs of FIG. 8 a and FIG. 8b relate to a conventional nucleation and deposition sequence. In eachof these comparisons the first photograph represents a magnificationnear 1000 time and the second a magnification near 15,000 times as isindicated in the photographs. These photographs or micrographs areobtained of course from a scanning electron microscope using theacceleration voltage and other parameters and the dimensional scalesindicated in the photographs. Additional numerical details regardingscanning electron microscope-obtained images appear below the photographin several photographs of this document and can be appreciated bypersons familiar with such apparatus.

Notably in the FIG. 8 photographs the conventional growth techniquediamond grains at the interface are quite large. The surface of thegrains is smooth, however, notice that the large grain size at theinterface results in large gaps between grains where there existsdomains of nondiamond carbon. Note also in the FIG. 9 photographs thatnot only are there large diamond grains at the interface and large gapsbetween the grains, but also that the surface of the grains is notsmooth. The surfaces of the larger FIG. 9 grains appear to be coveredwith much smaller sized grains in a secondary growth that significantlyincreases the surface roughness.

The FIG. 10 drawings-photographs show micrographs of the interface ofdiamond fabricated using the presently espoused and above discussedmodified novel nucleation process and an initially slower growth ratedeposition. Notice that the interface in FIG. 10 is very dense, with noapparent gaps between grains. Surface roughness is minimal, ranging from3 to 250 nanometers depending on the initial growth conditions andseeding procedures.

Other deposition procedures may be suitable for fabricating a verydense, smooth diamond interface to form the Integrated Diamond Carrierfrom the patterned substrate. However to obtain the desired very densediamond interface on the patterned substrate, the modified novelnucleation process is used with initial growth conditions in step 3 thatare slow and carefully controlled. The typical growth rate for the firstlayers of diamond growth in the modified novel nucleation process is 0.3micrometers per hour. After the dense interface is established thegrowth conditions can be altered to increase the growth rate, typicallyto 1-10 micrometers per hour. Higher growth rates are possible. Thediamond is then grown to a thickness of 200 micrometers or greater.

Examples of initial growth conditions follow.

EXAMPLE 15

Hydrogen/methane flow rates of 400/1.2 sccm,

Power of 2000 Watts,

Pressure of 60 Torr,

Temperature of 650 to 720 Celsius,

A growth rate of about 0.3 micrometers/hour.

EXAMPLE 16

A hydrogen/methane flow rate of 400/2 sccm,

Power of 2300 Watts,

A pressure of 60 Torr,

A Temperature of 650 to 720 Celsius,

A growth rate of about 0.3 micrometers/hour

The combination of a lower power level of 1500 to 2500 Watts, a cooledsubstrate holder and a methane/hydrogen ratio ranging from 0.2-0.5%,yields the lower growth rates and in combination with the seedingprocess, result in the very dense, smooth diamond interface desired forthe formation of the Integrated Diamond Carrier. Initial layers ofdiamond growth at the low growth rate may range in thickness and, thusin growth time from 1 to 30 micrometers.

Subsequent diamond growth to build up the Integrated Diamond Carrierstructure to at least 200 micrometers of thickness may proceed byvarious techniques. One such technique is by varying the depositionsconditions to grade the growth rate into several steps such that aninitial growth rate of about 0.3 micrometers/hour is followed by agrowth rate of about 0.5 micrometers/hour, a rate of about 0.7micrometers/hour, a rate of 1.2 micrometers/hour and a rate of about 2.4micrometers/hour.

Alternatively, the deposition conditions can be varied to obtain aninitial growth rate of about 0.3 micrometers/hour, then a rate of about0.7 micrometers/hour, then a rate of about 1.4 micrometers/hour, and arate of about 10 micrometers/hour. Varying the growth rates to obtaindiamond layers grown at graded growth rates is preferred overarrangements changing abruptly from a very low initial growth rate to avery high growth rate due to differences in film stress occurring in theachieved film. The various growth rates are obtained by increasing themethane/hydrogen ratio, increasing the power level and increasing thechamber pressure as noted in the following examples.

EXAMPLE 17

A growth rate of about 0.5 micrometers per hour is obtained with ahydrogen/methane flow rate of 400/2.4 sccm, a power of 2300 Watts, apressure of 60 Torr, and a Temperature of about 730 Celsius.

EXAMPLE 18

A growth rate of about 0.7 micrometers per hour is obtained with ahydrogen/methane flow rate of 500/4.0 sccm, a power of 2300 Watts, apressure of 60 Torr, and a Temperature of about 730 to 800 Celsius.

EXAMPLE 19

A growth rate of about 1.2 micrometers per hour is obtained with ahydrogen/methane flow rate of 500/6.0 sccm, a power of 2500 Watts, apressure of 65 Torr, and a Temperature of about 720 to 800 Celsius.

EXAMPLE 20

A growth rate of about 10 micrometers per hour is obtained with ahydrogen/methane flow rate of 800/12.0 sccm, a power of 4000 to 4500Watts, a pressure of 90 to 120 Torr, and a Temperature of about 750 to900 Celsius.

Once the diamond film as been built up to a level of 50 to 3000micrometers thickness, the deposition is discontinued. The sample isallowed to cool and then is removed from the deposition chamber. Thesubstrate is then fully etched using techniques described above, and thesingle, all diamond carrier consisting of arrays of mesa structures formounting laser bars, and a series of pyramidal mirrors for directing thelight of edge emitting lasers is formed.

Finally a thin metal coating of aluminum or silver can be applied to themirror side of the pyramidal structures to maximize the reflection ofthe laser light. Additionally, the mesa structures can be coated with athin, adhesion layer such as a layers of titanium/gold to facilitatebonding the laser bars to the diamond of the Integrated Diamond Carrier.

The carrier is then ready for mounting of the laser bars. The dimensionsof the spaces for the laser bars and the mirrors can be adjusted tooptimize the amount of light that is steered into the desired directionand to minimize light losses. The dimensions (width×length) of prototypecarriers are such as to facilitate laser performance and differentcooling techniques. In this regard it may be noted that the “length”dimension of the laser mounting mesa surface 112 in the FIG. 1 drawingis not specified and that a longer appearing dimension of 1100 um isshown for this feature in the FIG. 3 drawing. In short, these dimensionscan be varied to accommodate the details of a suitable thermalmanagement system.

The laser bars can be densely mounted on the mesa structures of thethusly-fabricated Integrated Diamond Carrier. Notably this IntegratedDiamond Carrier is grown as one solid piece of diamond. The light beamsemitted from the individual laser bars are aligned parallel to oneanother in a direction approximately 18 degrees off of vertical from thecarrier by the integrated diamond mirrors. The thermal resistance of thediamond carrier is low compared to conventional diode laser carriers(i.e., a value of about 0.001 degree Celsius/Watt for 1 squarecentimeter, assuming a 200 micrometer thick diamond layer beneath thelaser bars) because of the very high thermal conductivity of thediamond. FIG. 11 in the drawings shows a comparison graph of typicalthermal conductivity measurements for diamond films and furtherillustrates advantages achievable with the Integrated Diamond Carrier.

In the FIG. 11 drawing the broken vertical scale on the left ranges inthermal conductivity values between 0 and 22, the latter being a valueappropriate for bulk NNP diamond. The horizontal scale in this Figureshows deposited film thickness values ranging from 0 to 5000 nanometers.Along the right hand side of FIG. 11 is identified the materials such asCopper, Silicon and Aluminum providing the thermal conductivity valuesshown on the left hand scale. The lower curve in the FIG. 11 drawing,the curve represented by the “+” symbols represents thermal conductivityvalues for thin film copper and the upper diamond shaped curve valuesrepresent thin film diamond. Among the points of interest in the FIG. 11data are the significantly better thermal conductivity of diamond withrespect to that of the frequently used copper material in either thinfilm or bulk form and the fact that thin films of both copper anddiamond have differing thermal conductivity values from those of bulksamples of the same material. It is notable also in FIG. 11 that thediamond shaped conductivity points in the center portion of the FIG. 11drawing represent differing diamond thin film thermal conductivities andthese conductivities approach the bulk diamond conductivity as thickerfilms are considered. Since the diamond film of the present IntegratedDiamond Carrier is contemplated to be of 50,000 nanometers or greaterthickness it may be observed from the FIG. 11 data that thermalconductivity values near the high bulk diamond value are reasonablyincurred in the Integrated Diamond Carrier.

In the Integrated Diamond Carrier the laser bars are preferably mountedwith their top surfaces facing down so that the lasing region is closerto the diamond mesa. Indium is a preferred mounting material howeverother materials may be used. Between the heat source in the lasingregion of the laser bar and the diamond carrier in this mountingarrangement is approximately 5 microns of laser bar material (e.g. GaAs)and 3 microns of bonding material (e.g. indium). Assuming a high powerlaser system with 1000 W/sq.cm of heat to be dissipated, the temperaturegradient in the diamond carrier will be only 1 degree Celsius and thetemperature gradient from the laser bars to the heat sink will be lessthan 10 degrees Celsius. The thermal resistance of the describedarrangement is almost 50 times lower than the most advanced laserpackaging, the silicon monolithic microchannel developed by The LawrenceLivermore National Laboratory LLNL.

FIG. 12 in the drawings includes the views of FIG. 12 a and FIG. 12 band shows an experimental arrangement usable to demonstrate improvedlaser diode performance with the Integrated Diamond Carrier of thepresent invention. For this demonstration lasers may be fabricated fromsingle quantum well AlGaAs having graded index. These devices may bemounted with p-side up for this demonstration notwithstanding theadvantages of p-side down mounting described earlier. Mounting in FIG.12 a is to a copper CT-type mount using about 10 micrometer thick In/Sn(52%/48%) solder (in the top, no heat spreader, view) or in FIG. 12 b tometal of a 1 micrometer Ti/Au) coated Integrated Diamond Carrier ofabout 80 micrometers thickness using about 10 micrometers thick In/Sn(52%48%) solder and then mounting to the copper CT-type mount with anadditional 10 micrometers thickness of In/Sn (60%/40%) solder.

With no active cooling and no facet coatings of the two FIG. 12 lasersthe thermal path from the active region of the topmost laser for theFIG. 12 a condition “no heat spreader” is through approximately 100micrometers of GaAs substrate, about 10 micrometers of In/Sn solder tothe copper heat sink. The thermal path from the active region of thelaser for the FIG. 12 b condition “diamond heat spreader” isconsiderably longer and through approximately 100 micrometers of GaAssubstrate, about 10 micrometers of In/Sn solder, about 80 micrometers ofdiamond, about 1 micrometer of Ti/Au adhesion layer and about 10micrometers of In/Sn solder to the copper heat sink. Notwithstanding thelonger extent of the FIG. 12 b thermal path however, the path involvingthe Integrated Diamond Carrier, the rollover current for the laser isincreased by use of the Integrated Diamond Carrier mounting. A rolloverevent, as occurs in the FIG. 13 drawings, indicates the occurrence ofexcessive operating temperature in a diode laser thus increased inputpower level to a laser prior to rollover occurrence is desirable.

FIG. 13 in the drawings includes the views of FIG. 13 a, and FIG. 13 band shows a comparison of diode laser rollover event occurrences withuse of crude laser modules having two different densities ofincorporated lasers. In each of these drawings a comparison is madebetween a non cooled laser and a laser having thermal connection via aridge of the stated width connected to an Integrated Diamond Carrier.The FIG. 13 a drawing shows about a 15% improvement in total outputpower for 60 micrometer ridge width 808 nm Broad Area lasers. FIG. 13 bshows about a 20% improvement in total output power for 80 micrometerridge width 808 nm Broad Area lasers. These results are typical of theimprovements observed in a crude p-side up experiment. With a preferredp-side down mounting configuration, the shorter thermal path through thelaser bar (on the order of 5 micrometers as opposed to the p-side upexample which is on the order of 100 micrometers) will result in evengreater improvements in the laser performance because the thermalresistance essentially scales with the length of the thermal path (henceabout a 20× reduction results) through a given material.”

In other words, the semiconductor active region is 20× closer to thediamond so the heat generated as that much less material to travelthrough before reaching the diamond. So the diamond heat spreaderIntegrated Diamond Carrier can remove the heat from the source fasterbecause the source will be closer to the heat spreader. The activeregion of the laser bars thus stays cooler and significantly higherrollover current is achievable than in the p-side up configuration.

The present Integrated Diamond Carrier is contemplated to be an integralpart of an efficient thermal management system for diode laser arrays (apart that is suitable for use with spray cooling, jets, single phasecooling and other cooling techniques). The very same lasers that arebound to a certain operating power level today, because of limitationsin the heat dissipation capabilities of existing carriers, can beoperated at much higher power levels using the Integrated DiamondCarrier. The Integrated Diamond Carrier enables lasers to be operated athigher powers, provides a more uniform temperature field for laser barsand longer lifetimes because of the greatly improved cooling efficiency.The carrier will be more robust, less costly to fabricate and as much as50× more efficient than the most cutting edge technology in diode laserpackaging currently existing. The integrated beam steering mirrors ofthe Integrated Diamond Carrier simplify the process of aligning lightfrom the laser bar arrays.

Advantages

The achieved thermal resistance of the diamond carrier is notably lowwhen compared with that of conventional diode laser carriers, i.e., isabout 0.001 degree C./W for a 1 square centimeter thermal path crosssection assuming at least a 150 to 200 micrometer thick diamond layerexists beneath the laser bars. This thermal resistance of course occursbecause of the very high thermal conductivity of the diamond. The laserbars are preferably mounted with their top surfaces facing down so thatthe bar lasing region will be as close as possible to the diamondmaterial of the mesa. In addition, a material such as indium is used inthe junction at 113 between carrier and laser bar as a mounting andinterface supplement.

Thus, lying between the heat source in the lasing region of the laserbar and the diamond carrier is approximately 5 microns of laser barmaterial such as GaAs and the 3 microns of bonding material such asindium. Assuming a high power laser system with 1000 Watts per squarecentimeter of heat to be dissipated, the temperature gradient in thediamond carrier is only one degree Celsius and the temperature gradientfrom the laser bars to the heat sink is less than 10 degrees Celsius.The thermal resistance of this arrangement is thus almost fifty timeslower than the most advanced previous laser packaging arrangement, thesilicon monolithic microchannel.

The very same lasers that are today bound to a certain operating powerlevel because of limitations in the heat dissipation capabilities ofexisting carriers can be operated at substantially higher power levelsusing the present invention Integrated Diamond Carrier. The IntegratedDiamond Carrier also provides a more uniform temperature field for laserbars or other laser packaging arrangements and assures longer laserlifetimes because of the improved cooling efficiency achieved. As a ruleof thumb, every reduction of 10 degrees Celsius in laser operatingtemperature results in a doubling of the laser life. The IntegratedDiamond Carrier of the present invention is more robust, less costly tofabricate and as much as 50 times more efficient than the most cuttingedge technology in diode laser packaging, the SiMM. The integrated beamsteering mirrors of the Integrated Diamond Carrier also simplify theprocess of aligning the output light from the laser bar arrays.

When compared to the most cutting edge technology in diode laserpackaging, the SiMM, the Integrated Diamond Carrier is as much as 50times more efficient due to its substantially lower thermal resistance.This means that if the cooling surface is operating at 20 or 30 degreesCelsius, the laser bars packaged on the Integrated Diamond Carrier willbe operating at 25 to 35 degrees Celsius as compared to 70 to 80 degreesCelsius. This improvement offers the potential to revolutionize thediode laser-application field. Temperature uniformity over the laserbars is also improved as a result of diamond's high thermal conductivityand heat spreading capability. Coherent lasing can be achieved whileoperating at higher power levels than are possible for present diodelasers because the temperature variations between individual stripes orridge widths on a laser bar are smaller. This means that the outputpower for the same laser bars available commercially today can behigher. The fabrication of the Integrated Diamond Carrier is lesscomplex than that of current competing cooling arrangements such as theSiMM. The Integrated Diamond Carrier is essentially grown as a completepackage.

The basis for the Integrated Diamond Carrier concept is the fact thatdiamond has the highest thermal conductivity of all known materials andthis is most important with respect to high power dissipations asencountered in other semiconductor devices for example. There are forexample new applications for MEMS and MOEMS devices that can benefitfrom carriers customized to the particular application, but built thesame way as the laser bar Integrated Diamond Carrier. The ability togrow diamond conformally on a mold, opens up ways to use prefabricatedfixtures of diamond for other tools and work pieces that are notcurrently identified.

While the apparatus and method herein described constitute a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus or method and thatchanges may be made therein without departing from the scope of theinvention, which is defined in the appended claims.

1. The method of fabricating an integral laser diode array-mounting andcooling diamond heat sink structure comprising the steps of: forming asemiconductor mold member having a complementary inverse pattern surfaceregion with respect to a configuration needed for said diamond heat sinkstructure; pretreating said semiconductor mold member complementaryinverse pattern surface region to achieve a covering selected thicknessfilm of diamond seeding elemental carbon powder thereon; saidpretreating step including generating, with one of a chemical vapordeposition process and a multiple hot gas decomposition process, saidelemental carbon powder film on said mold member complementary inversepattern surface region; seeding said pretreated semiconductor moldmember complementary inverse pattern surface region with a coating ofdiamond powder; said seeding step including suspending said pretreatedsemiconductor mold member in a liquid suspension of diamond powder;growing a dense smooth film of diamond over said elemental carbon powderfilm covered and seeded semiconductor mold member, said growing stepincluding growth rates commencing with a slow first rate and progressingthrough a plurality of faster subsequent growth rates; continuing saidgrowing step at said faster subsequent growth rate until a diamond filmlayer of selected thickness between 50 and 3000 micrometers is achieved;dissolving said semiconductor mold member from said diamond film layerto achieve said laser diode array-mounting and cooling diamond heat sinkstructure.
 2. The method of fabricating an integral laser diodearray-mounting and cooling structure of claim 1 wherein said fabricatedstructure also includes an integral laser light deflecting element. 3.The method of fabricating an integral laser diode array-mounting andcooling structure of claim 1 wherein said step of forming asemiconductor mold member having a complementary inverse pattern surfaceregion with respect to a configuration needed for said diamond heat sinkstructure includes aligning said configuration needed for said diamondheat sink structure with a {111} crystal plane of a silicon materialcomprising said semiconductor mold member.
 4. The method of fabricatingan integral laser diode array-mounting and cooling structure of claim 1wherein said step of pretreating said semiconductor mold member toachieve a selected thickness film of diamond seeding elemental carbonpowder thereon includes pre treatment conditions of: a hydrogen flowrate of between 400 and 900 sccm; a methane flow rate of 1 to 9 sccmwith a methane to hydrogen gas flow rate ratio of less than two percent;a power level of 1500 to 4000 watts; a pressure of between 20 and 120Torr; a temperature of 500 to 900 degrees Celsius; a pretreatment timeof ten to 90 minutes.
 5. The method of fabricating an integral laserdiode array-mounting and cooling structure of claim 1 wherein said stepof seeding said pretreated semiconductor mold member with a coating ofdiamond powder includes one of seeding mixtures comprising: 2 grams ofnanodiamond powder in 200 ml of ethanol; 3.2 grams of 10 micrometerdiamond powder in 200 ml of methanol; 3.2 grams of 10 micrometer diamondpowder in 200 ml of ethanol; 2.2 grams of 10 micrometer diamond powderand 1 gram of 0.1 micrometer diamond powder in 200 ml of methanol; 2.2grams of 10 micrometer diamond powder and 1 gram of 0.1 micrometerdiamond powder in 200 ml of ethanol; 1.6 grams of 10 micrometer diamondpowder and 1.6 grams of 0.1 micrometer diamond powder in 200 ml ofmethanol; 1.6 grams of 10 micrometer diamond powder and 1.6 grams of 0.1micrometer diamond powder in 200 ml of ethanol; 1.0 grams of 10micrometer diamond powder and 2.2 grams of 0.1 micrometer diamond powderin 200 ml of methanol; 1.0 grams of 10 micrometer diamond powder and 2.2grams of 0.1 micrometer diamond powder in 200 ml of ethanol; 3.2 gramsof 0.1 micrometer diamond powder in 200 ml of methanol; 3.2 grams of 0.1micrometer diamond powder in 200 ml of ethanol; 200 ml of GeneralElectric Company diamond slurry 0-0.2 micrometer diamond formula K-285T;200 ml of South Bay Technology diamond suspension 0.1 micron diamond,P/N DS001-16; and 200 ml of Warren Superabrasives diamond suspension,0.5 micrometer diamond, type MB DIA-SOL, Lot 910T6.
 6. The method offabricating an integral laser diode array-mounting and cooling structureof claim 1 wherein said step of growing a dense smooth film of diamondover said elemental carbon film covered and seeded semiconductor moldmember includes initial growing conditions comprising one of: ahydrogen/methane flow rates of 400/1.2 sccm; a power of 2000 Watts; apressure of 60 Torr; a temperature of 650 to 720 degrees Celsius; and: ahydrogen/methane flow rate of 400/2 sccm; a power of 2300 Watts; apressure of 60 Torr; a temperature of 650 to 720 degrees Celsius; and aninitial growth rate of substantially 0.3 micrometers/hour.
 7. The methodof fabricating an integral laser diode array-mounting and coolingstructure of claim 1 wherein said step of growing a dense smooth film ofdiamond over said elemental carbon film covered and seeded semiconductormold member includes one of growing conditions comprising; ahydrogen/methane flow rate of 40012.4 scam; a power of 2300 Watts; apressure of 60 Torr; a Temperature of 730 degrees Celsius; and a growthrate of substantially 0.5 micrometers per hour; a hydrogen/methane flowrate of 500/4.0 sccm; a power of 2300 Watts, a pressure of 60 Torr; atemperature of 730 to 800 degrees Celsius; and a growth rate ofsubstantially 0.7 micrometers per hour; a hydrogen/methane flow rate of50016.0 sccm; a power of 2500 Watts; a pressure of 65 Torr; atemperature of 720 to 800 degrees Celsius; and a growth rate ofsubstantially 1.2 micrometers per hour; a hydrogen/methane flow rate of800/12.0 sccm; a power of 4000 to 4500 Watts; a pressure of 90 to 120Torr; a temperature of 750 to 900 degrees Celsius; and a growth rate ofsubstantially 10 micrometers per hour.
 8. The method of fabricating anintegral laser diode array-mounting and cooling structure of claim 1wherein said step of growing a dense smooth film of diamond over saidelemental carbon film covered and seeded semiconductor mold member iscontinued until a diamond film of 50 to 3000 micrometers thickness isachieved.
 9. The method of fabricating an integral laser diodearray-mounting and cooling structure of claim 1 wherein said generatedelemental carbon particle film has a thickness of between 5 and 10nanometers.